Schaumburg Castle, Lower Saxony, Medieval castle in Rinteln, Germany

Schaumburg Castle stands on the 225-metre Nesselberg above the Weser. The complex is divided into a lower outer bailey and a higher main castle; the oldest section occupies an oval plateau of 100 by 60 metres, enclosed by a 1.30-metre-thick curtain wall built in opus spicatum. The main building has a white facade, rows of dark rectangular windows and a red tiled roof with steep gables; a round red-roofed tower stands to its left.

Adolf I von Schaumburg built the castle on the Nesselberg on the remains of an earlier structure; it is first documented in 1119 and was the ancestral seat of the Counts of Schaumburg. Around 1390 Count Otto I added the ring wall and lower gate tower, and the palace was rebuilt in Renaissance style in 1521. After the main line died out in 1640 the castle passed to Hesse-Kassel, then to Prussia in 1866; in 1907 Wilhelm II gave it to Prince Georg of Schaumburg-Lippe, and in 2022 an entrepreneur couple bought it from the princely house.

The castle gave its name to the Counts of Schauenburg and Holstein and to the Schaumburg region, whose coat of arms carries the nettle leaf from the counts' ancestral shield. Outside the outer gate stands the Blutlinde, a lime tree about 600 years old; legend says a woman condemned in a witch trial around 1400 planted it while declaring her innocence.

The castle stands on the 225-metre Nesselberg, twelve kilometres east of Rinteln's centre, above the hamlet of Schaumburg. The keep, raised to 30 metres in 1908–1912, can be climbed as a viewing tower. The restaurant in the former manor house closed in 2017, and renovation work has been announced, so check access before setting out.

The keep was raised to its present 30-metre height only during the 1908–1912 restoration led by architect Albrecht Haupt, when the lower castle buildings were also renewed. Work on the upper castle was then halted by the First World War, and in 1945 American artillery fire damaged the buildings.